1. Field of the Invention
The present invention relates to a magnetic head slider flying above a magnetic recording medium with a small distance therebetween to record and reproduce magnetic information, and a manufacturing method therefor. Particularly, the present invention relates to a technique for improving the abrasion resistance of protrusions provided on the medium-facing surface and rails of a slider body while maintaining the manufacturing efficiency high. The present invention also relates to a technique for preventing corrosion of a magnetic head core provided on the slider body.
2. Description of the Related Art
As a conventional magnetic recording apparatus for a computer, the magnetic disk device shown in FIG. 27 is known.
This magnetic disk device comprises a magnetic head slider 82 provided above a rotatable magnetic disk 81 opposite thereto. The magnetic head slider 82 is supported by a support arm 84 through a triangular spring plate 83 so that the magnetic head slider 82 can be moved to a desired position in the diameteral direction of the magnetic disk 81 by rotation of the support arm 84 around the rotation center 84a. 
In the magnetic disk device shown in FIG. 27, with the magnetic disk 81 stopped, the bottom of the magnetic head slider 82 is lightly pressed on the magnetic disk 81 by urging force of the spring plate 83 for supporting the magnetic head slider 82, while with the magnetic disk 81 rotated, the magnetic head slider 82 flies and moves above the magnetic disk 81 at a predetermined height by means of an air flow accompanying rotation. When the rotation of the magnetic disk 81 is stopped, the flying and moving magnetic head slider 82 is again stopped by contact with the magnetic disk 81. However, in flying and moving, magnetic information is read from or written on the magnetic recording layer of the magnetic disk 81. The series of operations is generally referred to as “CSS (contact start stop)”.
FIGS. 28 to 30 are drawings showing the two-rail type magnetic head slider 82 conventionally used in a wide range. FIG. 28 is a side view showing a state in which the magnetic head slider 82 flies and moves, FIG. 29 is a side view showing a static state, and FIG. 30 is an enlarged sectional view of the magnetic head slider 82 taken along the length direction of side rails 86. The magnetic head slider 82 comprises a groove (not shown) formed at the center of the bottom thereof, and the side rails 86 formed on both sides of the groove. Each of the side rails 86 has an inclined surface 86a formed on the lower side at the front end thereof (on the upstream side in the rotational direction of the magnetic disk 81) so that air flows along the inclined surfaces 86a as shown by arrows A in FIG. 28 to float and move the magnetic head slider 82 by means of the bottom of the side rails 86 of the magnetic head slider 82, which serves as a positive pressure generating portion.
A magnetic head is also known, in which as shown by a two-dot chain line in FIG. 28, a negative pressure groove 86b is formed at the bottom of the side rails 86 so that the negative pressure produced by the negative pressure groove 86b and the positive pressure produced by the side rails 86 are balanced to stabilize flying and moving performance.
Furthermore, an adhesive film 91 of Si is formed on the surface of each of the side rails 86, and a first carbon film 92 is formed on the adhesive layer 91, as shown in FIG. 30.
FIG. 28 is a side view showing a state of the magnetic head slider 82. When the magnetic head slider 82 flies and moves, air flows to the bottom side of the magnetic head slider 82 through the inclined surfaces 86a, and with the negative groove 86b formed, negative pressure is produced on the rear side of the magnetic head. Therefore, the magnetic head slider 82 flies and moves in an inclined state at a small angle in which the air inflow side is inclined upward, as shown in FIG. 28. The inclination angle is generally referred to as a “pitch angle” (usually about 100 μRad).
The magnetic head slider 82 having the above-described construction is brought into sliding contact with the magnetic disk 81 when the magnetic disk 81 is started (rising) and stopped (falling). In order to prevent abrasion and wear of the surface of the magnetic disk, a protecting film is formed on the recording layer of the magnetic disk 81, and a lubricating layer is further formed on the protecting film.
In the magnetic head slider 82 having the above construction, from the viewpoint of magnetic recording, it is advantageous that during flying, the magnetic gap G of the magnetic head slider 82 is brought as near the magnetic recording layer of the magnetic disk 81 as possible. Therefore, in flying and moving, the height of the magnetic head slider 82 is preferably as low as possible. In recent years, the amount of flying (the spacing between the magnetic head slider 82 and the magnetic disk 81) of the magnetic head slider 82 has been further decreased with increasing recording densities and miniaturization of a magnetic disk device. In order to decrease the flying amount, the surface roughness of the magnetic disk 81 must be decreased as much as possible for avoiding contact between the magnetic head slider 82 in the flying state and the magnetic disk 81.
However, in starting or stopping the magnetic disk 81, the area of contact between the magnetic disk 81 and the magnetic head slider 82 increases as the surface of the magnetic disk 81 becomes smooth, to easily cause adhesion between the slider 82 and the magnetic disk 81. This increases adhesion torque to increase the load at the start of a motor for rotating the magnetic disk 81 and easily break the support arm 84, the magnetic head element provided on the slider or the magnetic disk recording layer at the start of rotation of the magnetic disk 81. Therefore, in order to solve this problem, protrusions 89 are provided on the air inlet side and outlet side of each of the side rails 86 through the adhesive layer and the first carbon film to decrease the area of contact with the magnetic disk 81. Each of the protrusions 89 comprises an intermediate film 93 made of Si, and a second carbon film 94 formed thereon. The first and second carbon film 92 and 94 generally comprise the same material from the viewpoint of manufacturing efficiency, etc.
An example of the manufacture of a conventional magnetic head slider having the above construction will be described below.
First, the adhesive layer 91 made of Si, the first carbon film 92, the intermediate film 93 made of Si, and the second carbon film 94 are deposited by sputtering on the medium-facing surface of a plate on the magnetic disk side thereof, which is composed of Al2O3TiC and comprises a magnetic head core 90. Then, the multilayer film comprising the adhesive layer 91, the first carbon film 92, the intermediate film 93 and the second carbon film 94 is patterned to form the side rails 86 and the groove therebetween on the medium-facing surface. The multilayer film remains on the surface of each of the side rails 86, and the surface of the plate is exposed from the groove between the side rails 86. Then, the intermediate film 93 and the second carbon film 94 on each of the side rails 86 are patterned to form the protrusion 89. As a result the magnetic head slider 82 shown in FIGS. 28 to 30.
In the conventional magnetic head slider having the above construction, in starting or stopping the magnetic disk 81, the protrusions 89 are readily worn due to friction in sliding on the magnetic disk 81, thereby causing the problem of deteriorating the effect of the protrusions 89. Therefore, as the material for the first and second carbon films 92 and 94, diamond-like carbon having good abrasion resistance is possibly used. However, the diamond-like carbon has low compactness and low degree of adhesion, and thus use as the material for the first carbon film 92 produces low corrosion resistance, causing the problem of deteriorating the magnetic core provided on the slider body.
When the surface area of the protrusions 89 on the magnetic disk side is decreased to decrease the area of contact with the magnetic disk 81, the adhesion force between the slider 82 and the magnetic disk 81 can be decreased. However, in this case, the planar pressure applied to the protrusions 89 is increased to cause the problem of increasing abrasion.
As described above, in the magnetic head slider, the height of the magnetic head slider 82 in flying and moving tends to be increased due to demand for increasing the recording density and decreasing the size of the magnetic disk device, and the pitch angle is accordingly decreased.
However, in the conventional magnetic head slider shown in FIG. 31, decreasing the pitch angle causes the protrusions 89b on the air flow outlet side (near the magnetic gap G) to project from the magnetic gap G toward the magnetic disk side during flying. In order to avoid this problem, the positions of the protrusions 89b are moved from the magnetic gap G to the air flow inlet side 82a by L1, as shown by a broken line in FIG. 31.
However, where the positions of the protrusions 89a are moved to the air flow inlet side 82a, at a stop of the magnetic disk 81, the portion (near the magnetic gap G) of the medium-facing surface of the magnetic head slider 82, where no protrusion is provided, adheres to the magnetic disk 81 due to a liquid lubricant film coated on the surface of the magnetic disk 81 to cause the problem of increasing adhesion torque.